Individuals with Autistic Spectrum Disorders (ASD) often perform better than typically developing (TD) individuals in simple, albeit difficult, visual search tasks. This ability is often attributed to a lack of drive for coherence or superior local processing. We compare thirty adults with ASD with forty-nine TD individuals and twenty-seven adults with anxiety (ANX) across two real-world visual search tasks. Individuals had to find either a number superimposed over a real-world scene ("œno context" condition) or an object located in a contextually relevant location ("œcontext" condition). Each participant completed forty-one trials in each condition, each with a unique scene. Eye movements were recorded using an SR Research EyeLink 1000 eyetracker. All groups performed better in the context condition. However, the ASD group was less accurate than both groups, across conditions. All groups were quicker to find the target in the context condition but the ASD group was slower than the TD group. Furthermore, the ASD group took longer to initiate their search, fixate on the target, and decide that they had found the target than the TD group. These results suggest that individuals with ASD are able to integrate contextual information to aid the search but that their previously seen visual search advantage may not transfer to visual searches of real-world scenes.

To find if video enjoyment was deeper for people with ADHD (attention deficit/hyperactive disorder) than for their non-ADHD peers, subjects with ADHD, and without, had their eye movement tracked during video exposure to determine average saccade rates. I interviewed subjects using pre-tested statements to establish periods of flow state (a measure of enjoyment). Results indicate that there is a deeper sense of enjoyment for people with ADHD, as subjects with ADHD passed a greater average time in flow state during video consumption (27% compared to 21%). Furthermore, the effects of flow state on the eye movement of those with ADHD was much greater than the effects of flow state on the eye movement of the non-ADHD control group. Average saccade rates jumped up 0.15 saccades per second when comparing out-of-flow to in-flow states for the ADHD group, while the average saccade rate for the non-ADHD group increased only 0.03 saccades per second when comparing out-of-flow to in-flow states. This helps further understanding of why people with ADHD consume more screen time than their non-ADHD peers; they may be more inclined to choose video consumption as an activity since the enjoyment they receive from video consumption is deeper and more frequent.

Crew coordination in the context of aviation is a specifically choreographed set of tasks performed by each pilot, defined for each phase of flight. Based on the constructs of effective Crew Resource Management and SOPs for each phase of flight, a shared understanding of crew workload and task responsibility is considered representative of well-coordinated crews. Nominal behavior is therefore defined by SOPs and CRM theory, detectable through pilot eye-scan. This research investigates the relationship between the eye-scan exhibited by each pilot and the level of coordination between crewmembers. Crew coordination was evaluated based on each pilot's understanding of the other crewmember's workload. By contrasting each pilot's workload-understanding, crew coordination was measured as the summed absolute difference of each pilot's understanding of the other crewmember's reported workload, resulting in a crew coordination index. The crew coordination index rates crew coordination on a scale ranging across Excellent, Good, Fair and Poor. Eye-scan behavior metrics were found to reliably identify a reduction in crew coordination. Additionally, crew coordination was successfully characterized by eye-scan behavior data using machine learning classification methods. Identifying eye-scan behaviors on the flight deck indicative of reduced crew coordination can be used to inform training programs and design enhanced avionics that improve the overall coordination between the crewmembers and the flight deck interface. Additionally, characterization of crew coordination can be used to develop methods to increase shared situation awareness and crew coordination to reduce operational and flight technical errors. Ultimately, the ability to reduce operational and flight technical errors made by pilot crews improves the safety of aviation.

The phenomenon of attentional bias to alcohol, where drinkers demonstrate a preference in allocating visual attention towards alcohol-related stimuli rather than neutral stimuli, is well-established. Studies detecting this phenomenon typically utilize computer-administered stimulus presentation tasks such as the visual dot probe task. Despite their frequency of use, these tasks do not represent the ways in which individuals typically encounter alcohol outside of the laboratory. Typical environments where alcohol is present allow individuals to move about freely and encounter alcohol while also being exposed to many other stimuli. This dissertation sought to implement a novel approach to assessing attentional bias in vivo, and identify how alcohol consumption might influence such in vivo attentional bias. This two-study dissertation utilized an in vivo task where participants looked freely around a room representing a recreational setting containing numerous objects while portable eye-tracking glasses monitored what an individual looked at and for how long. Target items of alcohol and neutral beverages were placed throughout the environment and fixation time spent on these objects was recorded. The first study of this dissertation examined attentional bias to alcohol-related objects across two identical testing sessions to understand the impact of novelty on allocation of in vivo attention. The second study tested individuals using the same in vivo assessment following a 0.30 g/kg dose of alcohol, a 0.65 g/kg dose of alcohol and a placebo. Participants also completed the visual dot probe task in order to measure and compare their attentional bias in a more traditionally implemented task to the novel in vivo approach. Results from the first study indicate that as the novelty of stimuli begins to wane and habituation to neutral stimuli occurs, attentional bias to alcohol-related objects emerges. This attentional bias was shown to be related to drinking habits, where heavier drinkers demonstrated increased attentional bias. The second study in this research found no discernible effect of alcohol consumption on in vivo attentional bias, but did identify a satiating effect of consumption on bias as measured by the visual dot probe task. Additional visual dot probe findings suggest the specificity of the effect of alcohol consumption on attentional bias. Together, these findings help inform whether there is benefit in utilizing an ecological model of measuring attentional bias and how the phenomenon might be measured in laboratory settings in the future.

Les spécificités de la dépression chez la personne âgée, tant sur le plan cognitif qu'émotionnel, peuvent rendre difficile son diagnostic. La dépression du sujet jeune se caractérise notamment par la présence d'un biais dirigé vers les informations négatives. Aucune étude n'a encore évalué les biais attentionnels chez le sujet âgé déprimé bien que le vieillissement modifie le traitement de l'information à valence émotionnelle. L'objectif de cette thèse était d'identifier le caractéristiques du traitement de l'information émotionnelle chez les sujets dépressifs âgés par l'étude des performances des systèmes saccadiques et des stratégies d'explorations visuelles en ayant recours aux techniques d'eye-tracking. Les résultats montrent chez ces patients une augmentation du temps de réaction aux tâches de prosaccades et d'antisaccades ainsi que du taux d'erreur comparativement aux sujets contrôles. Par ailleurs, l'augmentation du taux d'erreur et du coût temporel (différence entre le temps de réaction d'antisaccades et le temps de réaction des prosaccades) suggère que ces processus ne sont pas uniquement liés à un ralentissement global, mais qu'ils pourraient être aussi expliqués par une altération spécifique des mécanismes d'inhibition. Cette altération est corrélée à la sévérité de l'épisode dépressif. L'analyse des performances oculomotrices lors de la présentation de paires d'images à connotation émotionnelle a mis ei évidence un biais de positivité chez les sujets dépressifs âgés en comparaison à un groupe contrôle. L'utilisation des techniques d'eye-tracking a donc permis de préciser la nature des interactions entre le vieillissement et la dépression au niveau neurophysiologique et émotionnel. Les anomalies oculomotrices objectivées par ces tâches pourraient constituer des marqueurs de la dépression du sujet âgé. Les limites méthodologiques liées à l'utilisation de ces techniques ainsi que les applications cliniques potentielles comme par exemple l'aide au diagnostic différentiel entre la dépression et la maladie d'Alzheimer, entre le trouble unipolaire et bipolaire et comme facteur d'évaluation de la réponse aux traitements sont discutées. / The specificities of dépression in thé elderly, on both thé cognition and emotional level, may render its diagnosis difficult. Dépression in young patients is characterized by thé présence of bias directed toward négative information. No study has assessed thé attentional bias in thé elderly depressed although aging changes thé emotional information processing. The aûn of this thesis was to identify thé characteristics of thé emotional information processing in depressed elderly subjects by studying thé performance of saccadic Systems and visual explorations stratégies through thé use of eye-tracking techniques. Our results showed that depressed patients had a higher reaction time in prosaccade and antisaccade tasks as well as higher error rates than controls. Moreover, thé higher time cost of inhibition (i.e. antisaccade reaction time minus prosaccade reaction time) suggests that thèse processes may imply a spécifie impairment of inhibition processes. This altération was found to be linked to dépression severity. The analysis of oculomotor performance on thé présentation of emotional picture pairs has highlighted a positivity bias in elderly depressed patients compared to healthy controls. The use of eye-tracking technologies has been found to be useful to specify thé link between ageing and dépression on neurophysiological and emotional levels. In this thesis, we also discuss thé methodological limits related to thé use of thèse techniques as well as thé potential clinical applications in thé differential diagnosis between dépression and Alzheimer's disease, or between unipolar and bipolar dépression, as well as in thé prédiction of treatment response.

Pesquisas apontam que o DMTS tem se mostrado mais eficaz no estabelecimento de classes de equivalência e maior grau de relacionamento entre estímulos de uma mesma classe do que o SMTS. Uma explicação possível para essas diferenças é que o aumento no intervalo de atraso entre a retirada do estímulo modelo e apresentação dos estímulos comparação em procedimentos de DMTS leva a uma maior exposição dos participantes ao estímulo modelo. Essa hipótese se alinha a resultados obtidos em experimentos que avaliam parâmetros de observação no estudo de discriminações condicionais, que demonstram que maiores durações de fixação do olhar sobre estímulos modelo estão associadas a maiores porcentagens de acerto no aprendizado em tarefas de MTS de identidade com modelos múltiplos. O presente estudo teve como objetivo avaliar os efeitos do emprego de atraso sobre a formação de classes e sobre parâmetros de fixação do olhar sobre os estímulos modelo em tarefas de MTS a partir do rastreamento dos olhos. Nove estudantes de graduação ou pós-graduação foram expostos a um treino de discriminações condicionais com estrutura OTM para estabelecer as classes A1B1C1, A2B2C2, A3B3C3 e A4B4C4. Cada uma dessas classes foi associada a uma condição de atraso durante o treino: simultânea, atrasos 0s, 2s e 4s respectivamente. Posteriormente, foram submetidos aos testes das relações emergentes de equivalência CB e BC, e simetria BA e CA em tentativas de DMTS com atraso 0s. Sete participantes atingiram o critério de aprendizagem durante o treino e conseguiram formar classes. Apesar de todos os participantes que atingiram os critérios terem aprendido primeiro relações de DMTS, não foram observados padrões ou diferenças significativas no aprendizado das discriminações condicionais ou formação de classes em nenhuma das condições. A análise dos parâmetros de observação também não revelou diferenças significativas entre frequência e duração de fixações do olhar sobre o modelo em nenhuma nas tentativas de SMTS ou DMTS com qualquer valor de atraso. Todavia, foi observado um efeito de prática, com valores maiores de duração de fixação nos blocos iniciais do treino. Esses resultados sugerem, portanto, que o maior tempo de exposição aos modelos não é suficiente para explicar as diferenças observadas no estabelecimento de classes de equivalência em tarefas de DMTS. Entretanto, alinham-se com a perspectiva de que um maior engajamento em comportamento de observação pode estar relacionado a um maior controle de estímulos dados os resultados do efeito de prática / Researches have indicated that the DMTS has been shown to be more effective in establishing equivalence classes and a higher degree of relationship between stimuli of the same class than SMTS. One possible explanation for these differences is that the increase in the delay interval between the withdrawal of the stimulus model and the presentation of the comparison stimuli in DMTS procedures leads to greater exposure of the participants to the stimulus model. This hypothesis aligns with results obtained in experiments that evaluate observation parameters in the study of conditional discriminations, which demonstrate that longer fixation durations on model stimuli are associated with higher percentages of learning success in multiple-models identity MTS tasks. The objective of the presente study was to evaluate the effects of the use of delay on the formation of classes and on parameters of fixation of the look on the model stimuli in MTS tasks from the eye tracking. Nine graduate or postgraduate students were exposed to conditional discrimination training with OTM structure to establish classes A1B1C1, A2B2C2, A3B3C3 and A4B4C4. Each of these classes was associated with a delay condition during training: simultaneous, delays 0s, 2s and 4s respectively. Subsequently, they were submitted to the tests of the emergent equivalence relations CB and BC, and symmetry BA and CA in attempts of DMTS with delay 0s. Seven participants reached the learning criterion during the training and were able to form classes. Although all participants who met the criteria first learned DMTS relationships, no significant patterns or differences in learning conditional discrimination or class formation were observed in any of the conditions. The analysis of the observation parameters also did not reveal significant differences between frequency and duration of fixations of the look on the model in any in the attempts of SMTS or DMTS in any with any value of delay. However, a practical effect was observed, with higher fixation duration values in the initial training blocks. These results suggest, therefore, that the greater time of exposure to the models is not enough to explain the differences observed in the establishment of equivalence classes in DMTS tasks. However, they are aligned with the view that greater engagement in observation behavior may be related to greater control of stimuli given the results of the effect of practice

This thesis aims to study how infants actively look at different social figures: parents and strangers. To study infants’ looking behavior in “live” situations, new methods to record looking behavior were tested. Study 1 developed a method to record looking behavior in “live” situations: a head-mounted camera. This method was calibrated for a number of angles and then used to measure how infants look at faces and objects in two “live” situations, a conversation and a joint action. High reliability was found for the head-mounted camera in horizontal positions and the possibility of using it in a number of “live” situations with infants from 6 to 14 months of age. In Study 2, the head-mounted camera and a static camera and were used in a “live” ambiguous situation to study infants’ preferences to refer to and to use the information from parents and strangers. The results from Experiment 1 of Study 2 showed that if no information is provided in ambiguous situations in the lab, infants at 10 months of age look more at the experimenter than at the parent. Further, Experiment 2 of Study 2 showed that the infants also used more of the emotional information provided by the experimenter than by the parent to regulate their behavior.  In Study 3, looking behavior was analyzed in detail when infants looked at pictures of their parents’ and strangers’ emotional facial expressions. Corneal eye tracking was used to record looking. In this study, the influence of identity, gender, emotional expressions and parental leave on looking behavior was analyzed. The results indicated that identity and experience of looking at others influences how infants discriminate emotions in pictures of facial expressions. Fourteen-month-old infants who had been with both parents in parental leave discriminated more emotional expressions in strangers than infants who only had one parent on leave. Further, they reacted with larger pupil dilation toward the parent who was actually in parental leave than to the parent not on leave. Finally, fearful emotional expressions were more broadly scanned than neutral or happy facial expressions. The results of these studies indicate that infants discriminate between mothers’, fathers’ and strangers’ emotional facial expressions and use the other people’s expressions to regulate their behavior. In addition, a new method, a head-mounted camera was shown to capture infants’ looking behavior in “live” situations.

The purpose of the current thesis was to investigate the role of gaze direction, when making preference decisions. Previous research has reported a progressive gaze bias towards the preferred stimuli as participants near a decision, termed the gaze cascade effect (Shimojo, Simion, Shimojo & Scheir, 2003). The gaze cascade effect is strongest during the final 1500 msec prior to decision (Shimojo et al.). Previous eye-tracking research has displayed natural viewing biases towards the upper visual field. However, previous investigations have not investigated the impact of image placement on the gaze cascade effect. Study 1 investigated the impact of presenting stimuli vertically on the gaze cascade effect. Results indicated that natural scanning biases towards the upper visual field impacted the gaze cascade effect. The gaze cascade effect was reliably seen only when the preferred image was presented in the upper visual field. Using vertically paired stimuli study 2 investigated the impact of choice difficulty on the gaze cascade effect. Similar to study 1 the gaze cascade effect was only reliably seen when the preferred image was presented in the upper visual field. Additionally choice difficulty impacted the gaze cascade effect where easy decisions displayed a larger gaze cascade effect than hard decisions. Study 3 investigated if the gaze cascade effect is unique to preference decisions or present during all visual decisions. Judgments of concavity using perceptually ambiguous spheres were used and no gaze cascade effect was observed. Study 3 indicated that the gaze cascade effect is unique to preference decisions. Results of the current experiments indicate the gaze cascade effect is qualified by the spatial layout of the stimuli and choice difficulty. Results of the current experiments are consistent with previous eye-tracking research demonstrating biases towards the upper visual field and offering support for Prevics theory on how we interact in visual space.

Two novel personal calibration procedures that do not require active user participation are presented. These procedures, in conjunction with a state-of-the-art remote eye-gaze tracking (REGT) technology, allow estimation of the angle between the optical and visual axes (angle kappa) automatically without explicit/active user involvement. The first algorithm for the binocular estimation of angle kappa (BEAK) is based on the assumption that at each time instant both eyes look at the same point on a surface with a known geometry (e.g., a computer monitor). The sensitivity of the BEAK procedure to the geometry of the observation surface and to the noise in the estimates of the optical axis is studied both analytically and in computer simulations. Experimental results with 4 adult subjects suggest that with the current REGT technology angle kappa can be estimated with an RMS error of 0.5°. The second personal calibration algorithm (‘calibrate and validate’, CaVa) adopts a probabilistic approach to the estimation of angle kappa in infants. Even though the presentation of visual stimuli at known positions is part of the procedure, the CaVa algorithm does not require/assume continuous fixation on the presented targets. If an infant attends to roughly half of the presented targets, angle kappa can be estimated accurately and with high confidence. In experiments with five babies, the average difference between repeated measurements of angle kappa was 0.04 ± 0.31°. The second part of the thesis describes two methods for automated measurement of eye misalignment in adults and infants. These methods are based on the user-calibration-free (UCF) technology presented in the first part of the thesis. The first method is based on the clinical Hirschberg test. It is shown that the UCF-REGT technology can improve significantly the accuracy of the Hirschberg test by enabling the estimation of subject-specific parameters (the Hirschberg ratio and angle kappa) in infants. The maximum error in the estimation of the horizontal and vertical components of eye misalignment in five orthotropic infants was shown to be less than 1°, which is significantly better than the accuracy of a standard clinical Hirschberg test. Finally, a novel Eye-Tracker Based Test (ETBT) for the estimation of the maximum (manifest + latent) angle of deviation is presented. ETBT is based on the UCF-REGT system. ETBT allows free head movements and does not require continuous fixation on specific targets. Experiments with 22 adult subjects demonstrated a good agreement of 0.7 ± 1.7° between ETBT and the gold-standard clinical procedure—the altenate prism and cover test. A pilot study with 5 orthotropic infants and one infant with strabismus demonstrated that the ETBT can be used in infants.

Two novel personal calibration procedures that do not require active user participation are presented. These procedures, in conjunction with a state-of-the-art remote eye-gaze tracking (REGT) technology, allow estimation of the angle between the optical and visual axes (angle kappa) automatically without explicit/active user involvement. The first algorithm for the binocular estimation of angle kappa (BEAK) is based on the assumption that at each time instant both eyes look at the same point on a surface with a known geometry (e.g., a computer monitor). The sensitivity of the BEAK procedure to the geometry of the observation surface and to the noise in the estimates of the optical axis is studied both analytically and in computer simulations. Experimental results with 4 adult subjects suggest that with the current REGT technology angle kappa can be estimated with an RMS error of 0.5°. The second personal calibration algorithm (‘calibrate and validate’, CaVa) adopts a probabilistic approach to the estimation of angle kappa in infants. Even though the presentation of visual stimuli at known positions is part of the procedure, the CaVa algorithm does not require/assume continuous fixation on the presented targets. If an infant attends to roughly half of the presented targets, angle kappa can be estimated accurately and with high confidence. In experiments with five babies, the average difference between repeated measurements of angle kappa was 0.04 ± 0.31°. The second part of the thesis describes two methods for automated measurement of eye misalignment in adults and infants. These methods are based on the user-calibration-free (UCF) technology presented in the first part of the thesis. The first method is based on the clinical Hirschberg test. It is shown that the UCF-REGT technology can improve significantly the accuracy of the Hirschberg test by enabling the estimation of subject-specific parameters (the Hirschberg ratio and angle kappa) in infants. The maximum error in the estimation of the horizontal and vertical components of eye misalignment in five orthotropic infants was shown to be less than 1°, which is significantly better than the accuracy of a standard clinical Hirschberg test. Finally, a novel Eye-Tracker Based Test (ETBT) for the estimation of the maximum (manifest + latent) angle of deviation is presented. ETBT is based on the UCF-REGT system. ETBT allows free head movements and does not require continuous fixation on specific targets. Experiments with 22 adult subjects demonstrated a good agreement of 0.7 ± 1.7° between ETBT and the gold-standard clinical procedure—the altenate prism and cover test. A pilot study with 5 orthotropic infants and one infant with strabismus demonstrated that the ETBT can be used in infants.